Various types of face shields are known in the art, many of which are designed to protect the wearer against various occupational hazards. Such face shields are generally comprised of multi-components, such as a clear viewing/shield portion affixed to a helmet or visor unit and are generally fabricated of relatively thick, impact-resistant plastic. There are generally known and well described two preferred methods for fabricating a face shield with acceptable optical clarity. In the first method, the face shield may be injection molded in a mold that has a highly polished surface. Such processes generally require that the molded part have a thickness in excess of 0.040 inch (1.02 mm) to achieve reasonable polymer flow into the mold. Other than the thickness of the part, which is acceptable for most applications, this method produces very high quality precision parts of any desired configuration. In another method, a blank may be taken from an optically polished flat polymer sheet (the sheet is polished usually by pressing between two platens) and formed in a curved piece (i.e. cylindrical, not spherical) by heating the blank beyond its glass transition temperature and applying force in the direction of the desired curve. This method generally retains the optics of the original polished sheet, but is only suitable for simple curved pieces and cannot be utilized where the desired piece has a complex configuration. It is understandable, that there is a need in the medical profession (the term “medical” as used herein is intended to encompass the medical, dental and related professions) for a lightweight, preferably disposable, face shield to protect the medical professional from splattered body fluids so as to avoid the possibility of contamination therefrom. While certainly many of the heretofore known goggles and face shields might serve this purpose, such products tend to be bulkier and heavier than is desired by the medical professional, for example, such as dentists, and are costly.
Use of face shields has grown substantially in dental and medical professions, in response to the spread of AIDS and like infectious diseases, to prevent infection from body fluid splatter. It is well known, that the face shields are moistly supported on a wearer's head by a head band or head visor, with the face shield generally attached to the head band or visor such that the face shield is positioned in front of the wearer's face. Usually, the face shield is suspended directly from the edge or brim of a head worn visor to provide protection to a wearer's face. A frequent problem experienced by users of face shields is that currently known face shield devices are uncomfortable to wear, particularly for extended periods of time. Wearers must frequently reposition the face shield in order to minimize discomfort. Face shield devices which rely on entirely hard head bands tend to cause perspiration under the band or entirely hard strap, causing additional discomfort. Further, dentists, physicians, and other persons who rely shields on their face frequently have both hands occupied in difficult or complex medical procedures, and cannot free their hands to positionally adjust the face shield apparatus to reduce discomfort.
Another known deficiency common to conventional face shield devices is that the face shields are not readily detachable from the devices. Face shield device used in the medical and dental professions must be exchanged between treatment of each patient to avoid cross-infection or cross-contamination of patients. Many currently used face shield devices do not provide for easy removal or interchange of face shields or non-expensive face shield devices, so that contaminated face shields can be sterilized or disposed.
One more common problem inherent to many conventional face shield devices is that the face shields cannot undergo pivotal adjustment while on the wearer's head, or pivotal adjustment is difficult to make while the face shield is being worn.
Accordingly, there is a need for a face shield apparatus which is comfortable to wear, which is light weight, which provides for quick and easy detachment and re-attachment of face shields, and which provides for quick and easy pivotal adjustment of face shields while on the wearer's head. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in prior devices.
A face shield device attachable to the spectacles is described in the U.S. Pat. No. 4,843,643. Generally, this device comprises two small metallic bars each L-shaped and associated by means of an end portion thereof with one of the two temples of a pair of spectacles. The coupling is provided by means of rings of an elastic material, each whereof embraces a portion of a bar and of a temple arranged mutually side by side. The two bars thus associated with the spectacles are provided with two ends in front of said spectacles and parallel thereto, so that each is insertable in the opposite end of a hole which longitudinally traverses a monolithic cross supporting member, essentially parallelepipedal in shape. The monolithic cross member is longitudinally traversed by two vertical millings of grooves, one whereof extends in transverse cross section from the hole to the upper surface, the other one extending, again in transverse cross section, from a narrow central portion to a lower surface. The millings are the support and insertion seat for an upper portion of a rectangular shield or screen in transparent material and having antifogging surfaces, and are intended to allow a certain transverse elasticity to the monolithic element so as to provide both the friction for the rotation thereof about the center of the hole and the interchangeability of the shield. Thus, the visor is adapted to spectacles of all widths, since it is sufficient for this purpose to insert more or less deeply the ends in the hole.
This device is inconvenient considering that not all dentists (surgeons) wear regular spectacles (eye glasses with optical lenses) for vision correction, and second, the dentists who does not wear the eye glasses have to use the eye glasses frame (with plane glass/no optic lenses/) or eye glasses frame without any plane glass or lenses in order to provide the support for shield, that for most people not using regular spectacles is inconvenient and uncomfortable. Also, the use of the surgical mask surrounding the dentist's nose and mouth is preferably required with such shield. However, wearing such masks is hot and uncomfortable too. Putting the masks on and removing them are time consuming and often difficult. It is known, that surgical masks cause the wearer to re-inhale exhaled breath causing the CO2 content of the blood to rise, and the result of this may be increased heart and respiration rates and higher body temperatures and perspiration.
A face shield apparatus having a frame assembly instead of the spectacles is described in U.S. Pat. No. 5,692,522. This face shield apparatus includes a frame assembly and the detachable and replaceable face shield coupled thereto. The frame assembly generally comprises a pair of generally parallel, spaced apart side members which are joined to a front member, which is supported by the wearer's nose or forehead. Articulating tails are included on the frame side members. One or more posts are provided on the frame assembly which pivotally engage one or more sockets associated with the face shield and provide for pivotal adjustment of the face shield relative to the frame assembly.
This face shield apparatus is complex, inconvenient and not sufficiently reliable because of the presence of engaged posts and the mounting rod detachably coupled to face shield by means of a plurality of studs installed into corresponding holes in face shield. Also, the face shield apparatus is not reliable, because the weight of the shield portion (the shield with the frame portion located in the front of the dentist's face) is supposedly heavier than the weight of the rest of the frame portion (articulating tails and the appropriate side members with the pivotally engaged posts and sockets). This requires tighter coupling of the apparatus with the head of dentist (i.e. the construction of the frame does not provide reliable coupling of the apparatus to the dentist head).
Additionally, the shield's left and right sides are bended under “sharp” angle, that limits the dentist visibility in the “rib” areas. Another deficiency of this apparatus is that the dentist has to use the surgical mask with such face shield.
To avoid such deficiency of visibility limitation, the U.S. Pat. Nos. 6,016,808 and D375,583 disclose the face shield including semi-circular configuration of the shield. The face shield frame apparatus by the mentioned patents comprises a head worn frame assembly to which a face shield can be detachably coupled. The frame assembly includes a pair of generally parallel, spaced apart side members which are joined to a front member, which is supported by the wearer's nose or forehead. One or more receptacles are provided on the frame assembly which slidably engage one or more latch arms associated with the face shield support, or conversely, the receptacle may be attached to the face shield support and the latch arm attached to the frame assembly. The latch arm has a locking tab which fits within a slot on the receptacle to lock the latch arm to the receptacle when the latch arm is inserted into the receptacle. The latch arm can also be removed from the receptacle by depressing the locking tab so that it disengages from the slot.
The face shield apparatus by U.S. Pat. No. 6,016,808 has the same deficiency as the previous prior art, i.e. the mentioned face shield apparatus is not sufficiently reliable, because the weight of the shield portion (the shield with the frame portion located in the front of the dentist's face) is supposedly heavier than the weight of the rest portion of the frame portion (the side members, etc.). This requires tighter coupling of the apparatus with the head of dentist (e.g. the construction of the frame does not provide reliable coupling of the apparatus to the dentist head), and the face shield by U.S. Pat. No. D375,583 has the dentist's head and face protecting device coupling means providing not precise (tightened) adjustment considering the step-type size adjusting process instead of the evenness. Also, the dentist using either one of these shields has to use the surgical mask.
More reliable construction of the face shield device is described in the U.S. Pat. No. 4,701,965. The shield of this invention is supported by means of a band of a material such as polyethylene which is resiliently flexible. The center portion fits around the forehead of the wearer and extends around the sides of the head terminating in ends on either side which grip the head sufficiently strongly to hold the device in place without creating discomfort. Integral with and extending forwardly from the band, is a visor shaped in the manner of a conventional sun visor.
Also, the device generally includes studs projecting from the visor. A shield is detachably secured to visor. To facilitate the studs snapping into and out of the holes, radial slits are formed in the shield which provide prongs which engage under the studs. Thus, the shield may be snapped onto the visor or removed therefrom.
Particularly for dentistry, a filter of an orange plastic which filters ultraviolet or high wave-length the blue light is disposed across the shield at a level slightly below the nose. In normal use, the filter is out of the line of sight through the shield. it is known that dentists frequently use ultraviolet or blue light lamps (not shown) to cure plastic tooth-filling materials. By tilting the head upward and directing the eyes, the filter is interposed between the instrument emitting the ultraviolet light and the eyes of the wearer to protect against damage.
But, this device is complex and also does not provide reliable coupling with the dentist's head. Additionally, the dentist has to preferably use the surgical mask with such shield.
So, in all previously described prior art, the dentist (surgeon, person/wearer whose occupation is in the medical field) has to use the surgical mask (e.g. the masks of gauze, paper, etc.) surrounding the dentist's nose and mouth to prevent intercontamination of the doctor and patient.
The mask used for such purpose is shown and described in the U.S. Pat. No. 5,469,229. The protective eye shield by this invention is used together with the mask.
There are many known face shields of different constructions providing the possibility to avoid the surgical masks. For example, the one-piece protective face shield to protect against contamination from splattered body fluids is described in U.S. Pat. No. 5,088,114. This face shield has a configuration providing possibility to eliminate the surgical mask. The device includes a curved brow member which is adapted to substantially conform with and contact a wearer's forehead. The uppermost edge of the curved brow member is curved away from the wearer's forehead to avoid contact of the forehead with any sharp edges which might cause discomfort. A face shield body (also referred in the invention to as eye protective shield) extends first outwardly at surface, then downwardly from the curved brow member and is integral therewith. The face shield body is adapted to cover at least a portion of the wearer's face (i.e. at least the wearer's eyes) without contacting any part of the face below the forehead. When means for retaining the curved brow member against the wearer's forehead, such as elastic band, are affixed to the face shield. The face shield is fabricated as one-piece out of a transparent, optical grade, thermoplastic material.
The face shield body also comprises an upper viewing portion which is disposed in the wearer's viewing path. This viewing portion is bubble-shaped. The lower portion extends downwardly from the upper viewing portion, and more specifically, the lower portion at first extends outwardly slightly from the upper viewing portion, then downwardly, so as to create a deflecting point to direct exhaled air away from the upper viewing portion.
This device has a complex configuration that leads to high cost of manufacturing, and as result is expensive for dental offices. Also, such massive face shield is inconvenient, limits the dentist's breathing that is uncomfortable during dental procedure.
Thus, there is a great need in the art for the non-complex, non-expensive and convenient improved visor-type face shield for dentist eliminating the necessity of the surgical mask use, and which is comfortable to wear, which is light weight, which provides for quick and easy detachment and re-attachment of face shields, and which provides for quick and easy pivotal adjustment of face shields while on the dentist's head. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in prior art.